Cushioning device for freely-gyrating mechanisms.



No. 822,893. PATENTED JUNE 5, 1906.

J. 1:". HARRISON.

GUSHIONING DEVICE FOR FREELY GYRAT ING MECHANISMS. APPLIOATION FILED JAN.14. 1904.

WITNESSES; INVENTOR A TTORNE Y.

1 device and related UNITED STATES PATENT OFFICE.

JOHN F. HARRISON, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS- (JHALMERS- COMPANY, OF TION OF NEW JERSEY.

MILWAUKEE, WISCONSIN, A CORPORA- CUSHIONING DEVICE FOR FREELY-GYI RATING MECHANISMS- Specification of Letters Patent.

Patented June 5 1906.

Application filed January 14, 1904. Serial No. 188.977.

To all whom, it may concern:

Be it known that I, JOHN F.'HARRISON, a citizen ofthe United States, residin at Milwaukee, in the county of Milwau cc and State of Wisconsin, have invented certain new and useful Improvements in Cushioning Devices for Freely-Gyrating Mechanism, of I starting and stoppin as will be hereinafter more specifically set orth.

In the drawings, Figure 1 shows the said mechanical movement applied to a suspended flour-bolter, together with the cushioning parts of my invention. Fig. 2 shows a plan View of the cushioning device and a section of the arresting-pin on the line a 11:. Figs. 3 and 4 show a modification of the cushioning device.

The lower part of the bolter is shown at 1. This bolter-is suspended by freely-niovable rods 2 2, provided with hooks passing through eyelets 3 3, firmly attached to .fixed side rods 4 4, parallel with the vertical axis of the bolter and attached to a bottom plate 41 and a similar top plate. (Not shown.) The suspension may be made-in any other way permitting free movement of gyration inya horizontal planesuch as, for instance, by socalled reeds or flexible wooden strips. directly attached to the bolter and the part from which it is hung. The shaft 5, freely rotating in upper and. lower bearings in the bolter, carries an eccentrically-mounted weight 6 on its lower end, as shown, and also on its upper end. This weight may be rovided with small removable wei hts, as s own, in order to vary it. The-sha t is rotated from a vertical shaft mounted in a fixed bearing located above its upper end by any of the well-known driving connections permitting of free movement of the shaft in ahorizontalplane while rotating on a vertical axis, such as a connectin -shaft with two universal joints.

en the shaft 5, together the weight 6, is rotated at a certain speed, this weight, while constantly changing its position with regard tothe bolter, will by acting on its lever-arm impart to the bolter a constant tendency to change'its position in a direction which is exactly opposed to the direction of rotation of the weight, thus throwing it out to the other side of the neutral axis from the center of gravity of the weight. The amount of this throw will vary with the proportion of the weight of the bolter to that of the rotating weight with the lever-arm of the latter and with the s eed. By reason of this throwing out of tfie bolter, which throw is always in line with the radial direction of the weight, a gyratory motion around the neutral axis will be imparted to the bolter. With a constant proportion between the weight of the bolter, the rotating weight, and the leverarm of the latter a certain speed, called the critical speed of rotation, exists, in which perfect balance is attained, and the partswill assume a position wherein the vertical axls of the bolter will remain parallel to the neutral axis at a certain distance while gyrating around it. The amount of throw will be such that the moment of the mass of the bolter into the distance of its axis from the neutral axis will be equal and opposite to the moment of the weight into its distance from the center of gravity to the axis of the shaft, the two moments thus neutralizing each other. At a lower speed the parts will gyrate on a conical surface around the center ofsuspension of the-shaft. ical surface will be inverted.

It will be understood that the two weights, one at each end of the shaft, act as one of double the weight, and are thus arranged in order to balance the strain on the shaft When starting the mechanism, the influence of centrifugal force will act, through the weight, to throw the latter and the attached parts violently outward in the direction of the weight, producing irregular swinging motion. This will continue until the critical speed has been reached and the parts are in balance. The same action will occur in stopping and may occur during the operation of At a higher speed this conthe machine, if for any reason the speed does not remain constant. My device has been designed in order to take care of this irregular motion, which strains the parts unduly and may cause the bolter to swing out sufliciently to interfere with adjoining apparatus and to damage attached parts.

As shown in the drawings, an eccentric pin 7 is provided on the shaft, its eccentricity with regard to the axis of the shaft being equal to the desired throw. The outer side of this pin is in contact with the inner coil of a coil-spring 8 when the mechanism is at rest and is located on the side toward the weight, as shown in Fig. 1. The outer end of the coil-s ring is attached to the inner wall of an annu ar flanged ring 9, which is firmly bolted to the floor. When the machinery is started,

the pin works against the resistance of the spring, which prevents the parts from flying out too far and acts as a cushion, avoiding jar and breakage of the parts. As soon as the critical speed has been attained the pin will no longer contact with the side of the spring, but its axis will be coincident with the neutral axis-that is to say, the axis of the bolter when the parts are at rest and around which it gyrates. Upon slowing down or stopping, the spring-cushion will again come into action, the parts finally coming to rest in the full-line position.

Figs. 3 and 4 show a modification in which three spiral springs 10 are adjustably attached at e ual angles to each other by means of eye olts to floor-brackets 11. The inner ends of these'springs are attached to'a plate 12, having an opening in its center whose radius is equal to the throw plus half the diameter of the pin. The action ofthis device is precisely similar to that of the one previously described. The shaft and pin are shown in the position which they assume after equilibrium has been attained.

It is evident that the springs may be arranged in a different manner.

7 It will be understood that while the device is shown applied to a flour-bolter it is equally applicable to any other machines in which a gyrating movement is produced by the rotation of an unbalanced weight, such as coal-screens, sieves, &c.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A gyrating bolter comprising a sievebox, means for freely supporting. the sievebox, and an independent elastic means normally spaced from the bolter for restricting the abnormal outward throw of the bolter durin gyration.

' 2. n combinationwith a gyrating sieve ioning means for the pin, said pin and cushioning-means coacting to cushion the abnormal outward movement of the sieve-box in a radial direction.

3. In combination with a gyrating sieve-.

box, means for freely supportin the sieveeccentric pin on theshaft, and a fixed elastic cushioning device coacting with the pin.

5. The-combination ofa gyrating sievebox, means for freely supporting the sievebox for gyration, an eccentricallyweighted rotatable shaft mounted in the sieve-box, an eccentric pin on the shaft located in the plane of the axis of the shaft and the center of gravity of the weight, and a fixed spring means provided with a central 0 ening in line with the axis of rotation an coacting with the pin. 6. The combination of a gyrating sievebox, means for freely supporting the sievebox for gyration, an eccentrically-weighted rotatable shaft mounted in the sieve-box, an

eccentric pin on the shaft, and a fixed coil-- spring, the pin coacting with the sprin 7. The combination of a gyratingbolter, rods for freely supporting the bolter for gyration, an eccentrically weighted I rotatable shaft mounted in the bolter, a flexible driving connection for the shaft, an eccentric pin on the shaft, and a fixed cushioning-spring device provided with a central opening, the pin conta'cting with the wall of the central opening in Y the spring when the bolter is at rest and rotating around its axis when the bolter is gyrating in equilibrium.

n a bolter, a sieve-carrying frame sue-- pended to move freely laterally, an eccen trically-weighted vertical. revoluble shaft mounted in the frame, independent fixed means for limiting the extent ofthe gyratory movement of the frame comprisin a springstop secured to a fixed support an having a circular opening, and a pin on the shaft projecting into the opening.

9. The combination of a gyrating bolter, supporting means for the bolter preventing rotation, andindependent elastic means for restricting the abnormal outward throw of the bolter during gyration;

10. The combination of a gyrating bolter, means for preventing rotation of the bolter, and-independent elastic means for restricting the abnormal outward throw of the bolter during'gyration...

11. In a bolter, a sieve-box freely supbox, and a normally inoperative elastic re ported for gyration, an eccentrically-Weightmeans for restricting the abnormal outward ed rotatable means mounted in the sieve-box, throw of the bolter durin gyration. an eccentric means on the rotatable means, In testimony whereof f alfix my signature 5 and means coacting with the eccentric means in presence of two witnesses.

for restrictin the abnormal outward throw JOHN F. HARRISON. of the bolter uring gyration. Witnesses: 12. A gyratin olter comprising a sieve- RICHARD HoPPIN,

box, means for eely supporting the sieve- WILLIAM I. GREENLEAF. 

